Circle.lua

--[[Example percentages array

local percentages={
  {
  Percentage=12,
  Colour=colours.red
  },
  {
  Percentage=30,
  Colour=colours.blue
  },
  {
  Percentage=25,
  Colour=colours.green
  }
}]]

BackgroundColour = colours.lightGrey
ActiveColour = colours.blue
Percentages = {
        {
        Percentage=10,
        Colour=ActiveColour
        }
}
Filled = false
TextColour = colors.black
Radius = 1
SubType = "Circle"
ShowText = false

OnDraw = function(self,x,y)
self.Height = self.Radius * 2+10
self.Width = self.Radius * 2+10
    if self.SubType == "Circle" then
     drawCircle(x,y,self.Radius,self.ActiveColour,self.Filled)
    elseif self.SubType == "Pie" then
     drawPie(x,y,self.Radius,self.Percentages,self.Filled,self.BackgroundColour)
    end
end

function drawCircle(StartX, StartY, radius, colour, filled)
local Filled = filled or false
local percentages={
  {
  Percentage=100,
  Colour=colour
  }
}

ShowText = false
local BGColour = colour
drawPie(StartX,StartY,radius,percentages,Filled,BGColour)
end

function drawPie(StartX,StartY,radius, percentages, filled,BGColour)
local Filled = filled or false
local Radius = radius
local CenterX = math.floor(radius + StartX)
local CenterY = math.floor(radius  + StartY)
local first = true
local lastPercentage = nil
    --calculate arc
    for key, value in next, percentages do
      theta = nil
      if first then
        theta = 0
        first = false
      else
          theta = lastPercentage
      end

      lastPercentage = theta + math.rad((value.Percentage/100)*360)
        --[[check if somebody added an element pushing us past 100%]]
        if lastPercentage > math.rad(360) then
          --[[undo that and break this loop let us finish up.]]
          lastPercentage = lastPercentage - math.rad((value.Percentage/100)*360)
          break
        end

        if ShowText and Filled then
          --[[use start and end radian values to get starting/ending x-y
          cumulative based on how many slices]]
          segX2 = CenterX + Radius * math.sin(lastPercentage)
          segY2 = CenterY + Radius * math.cos(lastPercentage)
          segX1 = CenterX + Radius * math.sin(theta)
          segY1 = CenterY + Radius * math.cos(theta)
          --[[get centerpoint of arc called c]]
          c = math.atan2(segY1-segY2,segX1-segX2)
          --[[get proper quadrant based on ending angle
          atan2 should get this automagically apparently not however]]
          if(c - lastPercentage)<-math.pi then
          --[[notice their not really midpoint of the radius
          adjusted slightly to make it look prettier.]]
          --[[compensate for negative x values in relation to centerpoint
          if it was 0,0]]
          textX = CenterX + (Radius/1.3) * math.sin(c-2*math.pi)
          --[[flip y value atan2 seems to be interpreting a wrong 0 point]]
          textY = CenterY + (Radius/1.5) * math.cos(c-math.pi)
          else
          textX = CenterX + (Radius/1.5) * math.sin(c)
          --[[flip y value atan2 seems to be interpreting a wrong 0 point]]
          textY = CenterY + (Radius/1.5) * math.cos(c-math.pi)
          end
        end

      --draw arc
      while theta <= lastPercentage do
        x = CenterX + Radius * math.sin(theta)
        y = CenterY + Radius * math.cos(theta)
          if Filled then
            drawLine(CenterX,CenterY,x,y,value.Colour)
          else
            Drawing.WriteToBuffer(x, y," ",colours.white,value.Colour)
          end
        theta = theta + 0.01
      end--end drawing arc
      --[[Draw based on calculations for midpoint we got before drawing the
      slice that way we don't end up drawing underneath]]
      if ShowText and Filled then
        Drawing.DrawCharacters(textX, textY, value.Percentage.."%", TextColour, value.Colour)
      end
    end--end calculating arc
    --finish drawing circle
    if lastPercentage < math.rad(360) then
      theta = lastPercentage
        while theta < math.rad(360) do
          x = CenterX + Radius * math.sin(theta)
          y = CenterY + Radius * math.cos(theta)
            if Filled then
              drawLine(CenterX,CenterY,x,y,BGColour)
            else
              Drawing.WriteToBuffer(x, y," ",colours.white,BGColour)
            end
          theta = theta + 0.01
      end--end drawing arc
    end--end finish drawing circle
end

function drawLine(x1,y1,x2,y2,colour)
  for i = 0,1,0.03 do
    x = (x2-x1)*i + x1
    y = (y2-y1)*i + y1
    Drawing.WriteToBuffer(x,y," ",colours.white,colour)
  end
end

local function ParseColour(value)
  if type(value) == 'string' then
    if colours[value] and type(colours[value]) == 'number' then
      return colours[value]
    elseif colors[value] and type(colors[value]) == 'number' then
      return colors[value]
    end
  elseif type(value) == 'number' and (value == colours.transparent or (value >= colours.white and value <= colours.black)) then
    return value
  end
  error('Invalid colour: "'..tostring(value)..'"')
end

OnUpdate = function(self,value)
  if value == 'Percentages' then
    for key, subvalue in pairs(self.Percentages) do
    subvalue.Colour = ParseColour(subvalue.Colour)
    end
  end
end